The condemned killer now walks to the death chamber, knowing nothing can save him now.

“Myself and the chaplain, we're in the death house with the inmate,” O’Reilly explained.

It’s a process O'Reilly knows intimately.

Between 2004 and 2010, O’Reilly supervised 140 executions. The retired warden says each one was different.

“We had one guy that got in there, and he cracked jokes the whole time he was in there,” O’Reilly said. Among those executions, one was a woman, Frances Newton, in 2005.

“She didn’t give us any trouble. We treated her with as much dignity as we would anybody else that would be in there,” O’Reilly said.

He also watched over the execution of one of the most notorious criminals in Texas history: Angel Resendiz, the so-called “railroad killer” who traveled the country by rail, killing as many as 14 people, including Dr. Claudia Benton of West University Place.

“These are evil people,” O’Reilly said. “While I believe there's a lot of good in the world, there's also evil in the world."

O’Reilly says he sleeps well at night -- no nightmares, no regrets. “If you’re a warden at the Walls, you're gonna preside over executions,” O’Reilly said. “If that’s a problem for you, don't take the job."

On the day of execution, the prisoner would be brought to Huntsville from death row in Livingston. O'Reilly would meet with the prisoner that afternoon, explain the process to him or her, and as the final hour approached, he would say, “It’s time.”

A team of guards would strap the inmate into the gurney and then, IVs would be inserted into his arms.

O’Reilly’s would be the last voice the condemned would ever hear.

After that, by remote control, O’Reilly would turn on a light in another room where someone whose identity would be kept secret started the flow of drugs.

“He makes his final statement and then he goes to sleep,” O’Reilly explained.

The retiree looks back at his career and says supervising more executions than any warden in Texas history is not what he wants to be remembered by.

O’Reilly says he'd rather be remembered as a good and fair warden who was just doing his job.